Chinas President Xi Jinping today officially launched the worlds longest sea bridge that cost £14 billion to build and connects Hong Kong, Macau and mainland China. The 55-kilometre (34-mile) crossing, which includes a snaking road bridge and underwater tunnel, will open to traffic tomorrow at 9am local time, linking Hong Kong with the southern mainland city of Zhuhai and the gambling enclave of Macau, across the waters of the Pearl River Estuary. The submerged tunnel, which is under the Lingding Ocean near Hong Kong, is connected by two artificial islands. At 6.75 kilometres (4.2 miles) long and 40 metres (131 feet) deep, the tunnel creates a gap in the bridge that will allow cargoships to pass through the busy deltChinas President Xi Jinping today officially launched the worlds longest sea bridge that cost £14 billion to build and connects Hong Kong, Macau and mainland China.

The 55-kilometre (34-mile) crossing, which includes a snaking road bridge and underwater tunnel, will open to traffic tomorrow at 9am local time, linking Hong Kong with the southern mainland city of Zhuhai and the gambling enclave of Macau, across the waters of the Pearl River Estuary.

The submerged tunnel, which is under the Lingding Ocean near Hong Kong, is connected by two artificial islands each occupying 10,000 square metres (one million square feet). At 6.75 kilometres (4.2 miles) long and 40 metres (131 feet) deep, the tunnel creates a gap in the bridge that will allow cargo ships to pass through the busy delta.

Xi presided over an inauguration ceremony attended by Hong Kongs and Macaus city leaders at a new port terminal in Zhuhai.

The Hong Kong-Zhuhai-Macau Bridge includes a road bridge and underwater tunnel and will open to traffic tomorrow

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Chinese President Xi Jinping presides over the opening ceremony for the Hong Kong-Macau-Zhuhai Bridge in Zhuha today

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A general view of the East Artificial Island at the Hong Kong-Zhuhai-Macau Bridge. Vehicles will have to drive through the two man-made islands to get to the 6.7-kilometre (4-mile) -underwater tunnel and back out again at the other sidI declare the Hong Kong-Zhuhai-Macau Bridge officially open, Xi said in a one-line address, as digital fireworks exploded on a screen behind him at the indoor ceremony, before leaving the stage immediately.

Supporters of the multi-billion-dollar bridge promote it as an engineering marvel that will boost business and cut travel time, but critics say it is one more way to integrate Hong Kong into China as fears grow that the citys cherished freedoms are being eroded.

Chinas Vice Premier Han Zheng characterised the bridge as part of the development of the Greater Bay Area - a Beijing-driven project to create an economic hub linking nine southern mainland cities to Hong Kong and Macau.

At the ceremony he described the strategy as deployed and driven by Xi Jinping personally.

Hong Kong leader Carrie Lam said the bridge would help transform Hong Kong from a connector to a more active participant.

It is the second major infrastructure project tying Hong Kong to mainland China to launch in a matter of weeks, after the opening of a high-speed rail link last month that sparked criticism Hong Kong was giving away territory - with part of the terminus coming under mainland jurisdiction.

The main section of the new bridge is also considered mainland territory, even though Hong Kong was slated to pay at least half the cost of the project, according to the original blueprint from the citys government.

A view of the main entrance of the bridge section after the opening ceremony of the new bridge

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The mega bridge links Hong Kongs Lantau island to Zhuhai and the gambling enclave of Macau

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To construct the submerged tunnel, engineers had to drive more than 100 huge steel cylinders into the sandy bottom to form the foundations for the man-made islands, according to a previous report by Wired citing engineers of the project

Hong Kong cars and drivers travelling over it must comply with the laws and regulations of the mainland, the citys transport department said.

Building began in 2009 and has been dogged by delays, budget overruns, corruption prosecutions and the deaths of construction workers.

The total price tag is unclear but some estimates run to over 100 billion yuan (£11 billion).

To get to either side of the bridge, vehicles will have to drive through the two man-made islands and the 6.7-kilometre (4-mile) -underwater tunnel and back out again.

To construct the submerged tunnel, engineers had to drive more than 100 huge steel cylinders into the sandy bottom to form the foundations for the islands, according to a previous report by Wired citing engineers of the project.

Without the tunnel, the bridge would have been so tall its pylons would exceed the height limits for structures near Hong Kong International Airport.

Secretary for Transport and Housing Frank Chan previously said travelling time between Zhuhai and the Hong Kong airport would be shortened to about 45 minutes from four hours.

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Supporters of the project promote it as an engineering marvel that will also boost business and cut travel time

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An interior view of the Hong Kong Port Passenger Clearance Building of the Hong Kong-Zhuhai-Macau Bridge

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The total price tag has not been officially confirmed yet but some estimates run to over 100 billion yuan (£11 billion)

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Cable cars travelling in front of the Hong Kong-Zhuhai-Macau bridge off Lantau island in Hong Kong

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The multi-billion-dollar bridge will open to traffic tomorrow at 9am local time, a day after the opening ceremony

Hong Kong residents will only be granted a licence to cross into Zhuhai by car if they meet highly selective criteria, including holding certain mainland government positions or making major contributions to charities in the southern Chinese province of Guangdong.

Most people will need to travel on coaches and buses.

Some Hong Kong media reported that the physical condition of bus drivers would be monitored by cameras, including an alert sent if a driver yawns more than three times in 20 seconds.

Online commenters in Hong Kong complained about the bridges restricted access ahead of the launch.

Such a huge investment using the Hong Kong taxpayers money... yet basically it is not open to us at all, said one comment on the South China Morning Post website.

But residents in Zhuhai welcomed it.

I think this bridge will bring great convenience to the whole area of Zhuhai, Hong Kong and Macao, and promote the economic development of the whole area of the Pearl River Delta, resident Dang Zheiliang told AFP.

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Officials expect the bridge to be in use for 120 years and say it will boost businesses by cutting travel time by 60 per cent

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A shuttle bus attendant displays bus tickets at the Hong Kong Port Passenger Clearance Building of the crossing

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To get to either side of the bridge, vehicles will have to drive through the man-made islands and the tunnel and back out again

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The mega structure is the worlds longest sea crossing and the sixth longest bridge on earth

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A total of 420,000 tons of steel was used in the project, equivalent to 60 times the steel used to build the Eiffel Tower

China already lays claim to the record for the worlds longest bridge of any kind - the Danyang-Kunshan Grand Bridge, a viaduct which is part of a high-speed rail line.

Political analyst Willy Lam said the launch by Xi showed his support for Hong Kongs economic and political integration into the region, adding that the Pearl River Delta had long been the new growth pole of China.

It was also timed with a wider push to mark the 40th anniversary of Chinas economic reforms, against the backdrop of major challenges to the economy, including the escalating US-China trade conflict, Lam said.

China will mark the anniversary in December of the reform and opening up that was launched in 1978 under the late paramount leader Deng Xiaoping, moving away from a Maoist command economy and toward more market-oriented policies that transformed the country into the worlds second-large